postprocess, translate: add support for Büchi (not state-based)

spot/twaalgos/postproc.hh: Introduce options Buchi and
GeneralizedBuchi.  The latter is similar to TGBA but the former differs
from BA in that it does not imply state-based acceptance, since that
can be specified separately.  Also all other acceptance types are not
abbreviated, so those new names make more sense.
* NEWS: Mention that.
* spot/twaalgos/postproc.cc, spot/twaalgos/translate.cc: Adjust
to support Buchi and GeneralizedBuchi without breaking BA and TGBA.
* bin/autfilt.cc, bin/common_aoutput.cc, bin/common_post.cc,
bin/ltl2tgta.cc, doc/org/tut10.org, doc/org/tut12.org,
doc/org/tut30.org, python/spot/__init__.py,
tests/python/automata.ipynb, tests/python/langmap.py,
tests/python/misc-ec.py, tests/python/satmin.ipynb,
tests/python/satmin.py, tests/python/toweak.py: Use the new names.
* tests/Makefile.am: Add missing langmap.py.

tests/python/satmin.ipynb

@@ -265,7 +265,7 @@
     }
    ],
    "source": [
-    "aut = f.translate('det', 'BA'); aut"
+    "aut = f.translate('det', 'Buchi', 'SBAcc'); aut"
    ]
   },
   {